A method of this type is disclosed in EP Patent No. 0 444 109 B1, for example. This publication describes a method and a device for determining tire prints, for the conversion thereof into forces which act on the tires and for improvement of the driving performance of the vehicle. Beside tire sensors which sense the tire contact, there are provided still other sensors, such as sensors for sensing the wheel circumferential speeds, the steering angle of the wheels, the position of the wheel suspensions and the center-of-gravity acceleration. The control method discloses sensing the forces and torques which act on the respective tire by way of tire print sensors. The forces and torques found are used, along with the other sensor means, to control the movement of the automotive vehicle. The above publication does not disclose which physical quantity is the actual control quantity used by the method.
It is state of the art, for example, to perform yaw torque control where a nominal yaw rate is compared with an actual yaw rate and, in the event of a discrepancy of the actual yaw rate from the nominal yaw rate, this difference is converted into control signals for defined correction elements. Operation of the correction elements will then cause the actual yaw rate to approach the nominal yaw rate. When, according to the above-mentioned publication, a defined physical quantity such as the rotational speed of the wheels shall be controlled selectively, it is assumed that this speed is also the control quantity. Initially, the forces which act on the wheels must be processed to calculate a nominal speed of the wheels. Matters are similar with respect to the steering angle or the position of the wheel suspensions of the wheels. The signals of the tire contact sensors are each time converted into the physical quantity respectively being controlled in order to compare an actual vehicle performance with a nominal vehicle performance. This necessitates a major expenditure in calculations because the physical quantity underlying the control cannot be determined directly, but only in a complicated fashion by converting tire contact signals into tire forces and torques and by further processing them into the physical quantity. Such a complicated processing of signals necessitates a considerable length of real time, thereby entailing a long reaction time until control intervention. The actual physical quantities which result at the end of such a complicated calculation are no longer relevant at the time they are calculated: The control quantity of the method will suffer because the control intervention which is performed with delay only may possibly not satisfy the demands of the actual driving situation.
Therefore, an object of the present invention is to provide a method of controlling the driving performance of a vehicle, utilizing tire sensors, which method permits a quickest possible reaction to a critical driving performance by way of a controlling intervention.